Transducer enclosure with variable moisture proofing

ABSTRACT

An enclosure for an ultrasonic transducer is configured for variable moisture protection. During storage and transport, the enclosure may be kept in a sealed state, which prevents entry of humidity. During operation in a wet environment (e.g., in a water meter attached to a pipe) water leaks into the enclosure very slowly, even when sealed. Accordingly, a tube is opened, allowing water molecules to be exhausted from the enclosure and absorbed by a desiccant within the water meter. In an example, a tube passes from an interior of the enclosure to an exterior of the enclosure. An end cap on the tube prevents humid air from entering the enclosure during storage and transport of the ultrasonic transducer. During operation in a humid environment, removal of the end cap allows air exchange to ventilate the enclosure and allows a desiccant outside the enclosure to absorb humidity exhausted from the enclosure.

RELATED APPLICATIONS

This patent application is a continuation of U.S. patent applicationSer. No. 16/588,844, titled “Transducer Enclosure with Variable MoistureProofing,” filed Sep. 30, 2019, which claims benefit of priority to U.S.Provisional Patent Application Ser. No. 62/869,988, titled “UltrasonicTransducer,” filed on Jul. 2, 2019, the entirety of both which areincorporated herein by reference.

BACKGROUND

Utility meters (e.g., water and gas meters) may include ultrasonictransducers and other components. The design requirements for suchmeters include issues of quality, accuracy, power consumption, and cost.In a first example, improved techniques for manufacturing and assemblyof a transducer and a printed circuit board (PCB) of the utility meterwould increase quality and reduce costs.

In a second example, storage and transport periods of the transducerlifecycle may include relative humidity 50 to 100 percent. However, inan operating environment, it is common small amounts of water to leakinto the enclosure of a transducer, and for the use of desiccant toreduce the humidity levels to 10 percent or less. Accordingly, anenclosure of a transducer that is more compatible with such variances inrelative humidity during different periods of the lifecycle would beadvantageous.

In a third example, known enclosures for transducers have failed toconduct ultrasonic signals with low losses and consistency and/or failedto provide the needed structural strength. Accordingly, improvedtechniques would result in increased signal strength and signalconsistency, as well as greater physical strength and resistance topressure.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is described with reference to the accompanyingfigures. In the figures, the left-most digit(s) of a reference numberidentifies the figure in which the reference number first appears. Thesame numbers are used throughout the drawings to reference like featuresand components. Moreover, the figures are intended to illustrate generalconcepts, and not to indicate required and/or necessary elements.

FIGS. 1 through 11 show example transducer assemblies that may beconverted from a moisture-proof state suitable for storage and/ortransport to an operational state that allows a desiccant to removemoisture.

FIG. 1 is a diagram showing an example of a lifecycle of a meteringdevice, transducer assembly and/or transducer device within such anassembly, and particularly showing how relative humidity varies over thelifecycle.

FIG. 2 is a view of an example ultrasonic transducer assembly in a highhumidity environment, particularly showing a sealed and waterproofconfiguration to resist the humidity.

FIG. 3 is a view of portions of an ultrasonic transducer assemblyshowing example structures configured to adapt and/or transition thetransducer from a high humidity environment to a low humidityenvironment.

FIG. 4 is an example transducer assembly shown in cross-section.

FIG. 5 is a further view of portions of the transducer assembly, showingthe epoxy resin and a channel to allow humidity transfer.

FIG. 6 is a cross section, showing an example arrangement of atransducer assembly, including a piezo device and a channel to transferhumidity.

FIG. 7 is a view of an example enclosure of an transducer assembly witha closed channel, suitable for shipping, storage and pre-installationsituations.

FIG. 8 is a view of an example enclosure for an ultrasonic transducerassembly transitioning from a closed channel to an open channel.

FIG. 9 is a view of an example ultrasonic transducer assembly with anopen channel, suitable for operational situations.

FIG. 10 is a cross-sectional view of an example transducer assembly inan operational configuration with the channel opened.

FIG. 11 is a cross-sectional view of a utility meter having twoinstalled transducer assemblies, both configured with open channelsconsistent with operation of the utility meter.

FIGS. 12 through 22 show example transducer assemblies, includingultrasonic sensor devices and associated enclosures, configured forautomated assembly with a printed circuit board and/or other componentswithin a utility meter.

FIG. 12 is a view of an example transducer assembly having an enclosurewith a two-portion plug connected to an upper portion of the enclosure.

FIG. 13 is a cross-sectional view of an example transducer assembly andan associated two-portion plug.

FIGS. 14 through 19 show an example sequence of actions or steps used ina method to install a metering device, including installation of atransducer on a water or gas pipe and soldering of wiring of thetransducer to electrical contacts of a PCB.

FIG. 20A is a diagram showing a first example plug of an enclosure of atransducer assembly, showing the plug in a configuration appropriate forstorage and transport before installation in a metering device.

FIG. 20B is a diagram showing the first example plug of the enclosure ofthe transducer assembly, showing the plug in a configuration afterinstallation in the metering device.

FIG. 21A is a diagram showing a second example plug of an enclosure of atransducer assembly, showing the plug in a configuration appropriate forstorage and transport before installation in a metering device.

FIG. 21B is a diagram showing the second example plug of the enclosureof the transducer assembly, showing the plug in a configuration afterinstallation in the metering device.

FIG. 22A through E are diagrams showing frangible areas of the plug ofan enclosure for a transducer and showing how movement of portions ofthe plug is performed during assembly of the example plugs atmanufacture and/or installation of the transducer assembly in a meteringdevice.

FIGS. 23 through 26 show example designs of ultrasonic transducerassemblies, including enclosures/housings and ultrasonic transducerdevices.

FIG. 23 is a cross-sectional diagram of an ultrasonic transducerassembly having a piezo transducer within a plastic enclosure thatcontains zero percent glass fiber.

FIG. 24 is a cross-sectional diagram of an ultrasonic transducerassembly having a piezo transducer within a plastic enclosure that is40% glass fiber.

FIG. 25 is a cross-sectional view of a first example of an ultrasonictransducer assembly having a piezo transducer within a bi-materialplastic enclosure, having portions that are made of materials havingdifferent characteristics and/or compositions.

FIG. 26 is a cross-sectional view of a second example of an ultrasonictransducer assembly having a piezo transducer within a bi-materialplastic enclosure, having portions that are made of materials havingdifferent characteristics and/or compositions.

DETAILED DESCRIPTION

Overview

In a first example, the disclosure describes techniques for providing anultrasonic transducer (usable in some examples in a water meter, gasmeter, or other device) having features and techniques for maintainingthe transducer in a waterproof state and a non-waterproof state. Aftermanufacture (e.g., during storage and transportation), ambient relativehumidity can vary widely, and may reach levels that are too high. Suchhumidity may degrade electronic components such as an ultrasonictransducer (e.g., a piezo device). In some cases, the high humidity maydamage the glue that couples the piezo device to the housing.Accordingly, example features and techniques hold the transducer in awaterproof state during these times. Upon installation in a water meteror other device, the transducer is transitioned to a non-waterproofstate, to thereby allow water to be exhausted from the transducer. Inoperation of a water-metering device, water may enter the transducer insmall quantities. A desiccant may be used to lower the humidity in theenvironment of the transducer. Because the transducer is in thenon-waterproof state, any small quantities of water that entered thetransducer are removed from the transducer and absorbed by thedesiccant. In an example, a tube may provide a channel within thetransducer. At one end of the channel is an area near the piezo deviceand associated glue attaching it to the housing and/or enclosure. At theother end of the channel, an end of the tube protrudes from theenclosure of the transducer. In the example, a frangible end of the tubecan be broken off. Prior to breaking the end of the tube, the transduceris in the waterproof state, and the internal components such as thepiezo device and glue attaching it to the enclosure are protected fromhumidity. The state is considered waterproof at least in part becausethe environmental conditions during storage and transportation are notnearly as wet as they are in the operational mode, and the transducer isessentially waterproof. After breaking off the end of the tube, thetransducer is in the non-waterproof state. In an operative state, somewater may enter the transducer's enclosure. Accordingly, bytransitioning to the non-waterproof state, water can be removed. Thus,any moisture entering the transducer, such as from condensation on apipe to which the transducer is attached, may exit through the open endof the tube, where the moisture is absorbed by the desiccant.Accordingly, before and after installation and operation, the piezounit, glue and other transducer components are held and maintained in asufficiently low humidity environment.

In a second example, the disclosure describes techniques for providing aplug to protect and guide wiring during storage, transportation, and themanufacturing process. The techniques provide for an improved connectionbetween the transducer and an electronic printed circuit board (PCB) andallow for a fully automated manufacturing process. In the example, aplastic plug is configured for insertion into an enclosure of atransducer. Two wires (e.g., electrical cables) extend through passagesdefined in two wire guides on an upper portion of the plug. In anexample, an assembly process attaches the wires of the transducer to aPCB.

In a third example, the disclosure describes advantages of a transducerassembly having a bi-material enclosure. In a more specific example, aplastic housing with mechanical reinforcements (e.g., 40% glass fiber)provides the advantage of strength and resistance to a high-pressureenvironment encountered during use. Transducer assemblies using aplastic sleeve having little or no reinforcing materials may provideless variations in signal transmission between assemblies than suchassemblies having reinforcing materials. Removing reinforcing materialsfrom the plastic sleeve obviates concern over variations in fibercontent and/or alignment. Removing reinforcing material from the plasticsleeve also obviates concern over the quality of fiber coatings, whichmay become exposed after wear and create a moisture-entry path.Accordingly, the bi-material transducer enclosure provides resistance topressure and consistency between transducer assemblies.

Transducer Enclosure with Variable Moisture-Proofing

FIGS. 1 through 11 show examples by which example transducers may beconverted from a waterproof state suitable for storage and/or transportto an operational state that allows water molecules to be exhaustedthrough an open tube and to be absorbed by a desiccant to removemoisture from the transducers.

FIG. 1 shows an example of a lifecycle timeline 100 of a transducer fora metering device. The first period 102 in the lifecycle (e.g., zero toeighteen months) the transducer may be subject to high humidity (e.g.,50% to 100% relative humidity). Humidity may damage electroniccomponents, the piezo device, and/or glue attaching the piezo device toa housing or enclosure of the transducer. Accordingly, the transducermust be protected from the humidity, and an enclosure of the transducermust be in a waterproof mode, state and/or condition. After installationat time 104, the transducer and an associated water or gas meteringdevice may have a 15- to 20-year lifespan 106. During the lifespan 106,any humidity entering the enclosure must be exhausted from theenclosure. Water may enter the enclosure of the ultrasonic transducerdue to that enclosure's connection and/or proximity to water or gaspipes. Accordingly, an opening in the enclosure is used to exhaustand/or transfer any moisture and humidity from the enclosure. Such watermay be transferred to a desiccant within the water or gas meter. Thisprocess keeps the humidity within the metering device quite low (e.g.,less than 10% relative humidity). Because the transducer must be able toexhaust any humidity to the desiccant, it is in a non-waterproof mode,state and/or condition during the operating period 106.

FIG. 2 shows an example transducer assembly 200, having an enclosure202. Within the enclosure, the transducer assembly 200 may include anultrasonic sensor (e.g., a piezo device), wiring, glue, layers of epoxyor plastic, backing, a humidity-exhausting tube, etc. The transducerassembly 200 is shown in a waterproof state to protect it from a highhumidity environment. The waterproof state obviates the need to pack thetransducer in desiccant during the storage, warehousing, transportationand/or inventorying phases of its lifecycle. The waterproof state alsoreduces failure rates that would accompany the failure of such desiccantduring wet environments, poor warehousing techniques, etc.

FIG. 3 shows a portion of the transducer assembly 200. In the exampleshown, a plastic tube 300 connects the internal areas of the transducerassembly (not shown) to the atmosphere outside the enclosure of thetransducer (e.g., the interior of the metering device). The tube 300shows a closed end-cap 302 of the plastic tube 300, which results in awaterproof state or mode of the transducer assembly 200. The waterproofstate or more is associated with the storage, transportation and/orwarehousing stages of the lifecycle of the transducer, before it isinstalled on a water pipe and/or in a meter. A thin or frangible region304 of the tube 300 allows the closed end-cap 302 of the tube to beeasily broken off. With the end-cap broken off, an open channel of thetube provides ventilation between an interior of the transducer assembly200 and atmosphere outside the enclosure portion of the transducerassembly. After the end-cap 302 of the tube is broken off, thetransducer assembly 200 is in the non-waterproof state or mode. Thenon-waterproof state or mode allows water that essentially cannot bestopped from very slowly entering the enclosure of the transducerassembly 200 to be exhausted (through tube 300) at a similar rate,thereby keeping the relative humidity within the enclosure of thetransducer assembly at a low level. The non-waterproof state or mode isassociated with the 15 to 20-year operational life span of thetransducer assembly 200.

FIG. 4 shows an example transducer assembly 200 in cross-section. Thetransducer assembly 200 of the transducer is configured to protect anultrasonic transducer and other components both in storage and afterinstallation in a metering device. The tube 300 defines a channel 400that provides ventilation (if the open state, with end-cap 302 removed)between the atmosphere and the region 402 within the enclosure 202 ofthe transducer assembly near the ultrasonic device. The tube 300 has anend-cap 302 which may be broken off at a frangible or weakened location304. Accordingly, when the endcap 302 is present, the channel 400 of thetube 300 is sealed, and the enclosure is in the waterproof state forwarehousing, transportation and/or inventory. When the end-cap 302 isremoved, the channel 400 of the tube 300 provides ventilation from theinside of the enclosure 202 to the atmosphere outside the transducerassembly, and the enclosure is in the non-waterproof state or mode. Thenon-waterproof mode allows small amounts of water that cannot beconveniently stopped from entering the enclosure 202 of the transducerto be exhausted out the channel 400 of the tube 300 and into a desiccantover an approximately 20-year operating lifetime of the transducer.

FIG. 5 shows a portion of the enclosure 202 of a transducer assembly200. In the view shown, the tube 300 of the enclosure 20 of thetransducer extends through a layer 500, which provides structuralsupport and water-proofing. In an example, the layer 500 is made ofepoxy resin. Accordingly, the tube 300 passing through the resin layer500 is held in place in a waterproof manner.

FIG. 6 shows portions of the example enclosure 202 of a transducerassembly 200, and an arrangement of components within the enclosure,including an ultrasonic (e.g., piezo) device 600 and glue 602 sealingthe piezo device to a base portion of the enclosure. The channel 400 ofthe tube 300 is configured to transfer humidity from the area of thepiezo device to the atmosphere (if the end-cap has been removed). Theview shows a layer of epoxy resin 500 and a layer of silicon glue 604.

FIG. 7 shows an example enclosure 202 for an ultrasonic transducerassembly 200 with a closed channel, suitable for warehousing, shipping,storage and pre-installation situations. The tube 300 defining a channelis sealed by the end-cap 302. The frangible region 304 has not bebroken. Accordingly, the enclosure 202 is in the waterproof condition,phase and/or mode of the transducer lifecycle.

FIG. 8 shows an example process by which the tube 300 and associatedinternal channel (channel 400, seen in FIG. 4 ) is opened. The processinvolves breaking the frangible region 304 (shown in FIG. 7 ) to therebyremove the end-cap 302. The process transitions the enclosure 202 for atransducer assembly 200 from the waterproof configuration used forshipping, storage and/or pre-installation situations to a non-waterproofconfiguration used during operation. Because the waterproof conditionmay not be truly waterproof in an operating environment, the transduceris kept drier by having the tube 300 open, to thereby allow water to beremoved from the enclosure 202 of the transducer assembly 200 andabsorbed by the desiccant within an enclosure of a metering device.

FIG. 9 shows an example enclosure 202 for ultrasonic transducer assembly200 with an open channel 400 of the tube 300 channel 406, suitable foroperational situations. The endcap has been removed and is not shown.The tube 300 is open because the frangible region has been cut or brokenduring the assembly and/or manufacturing process, thereby releasing theendcap.

FIG. 10 shows an enclosure 202 for a transducer assembly 200 in anoperational configuration with the channel 400 within the tube 300 in anopened condition. In the view shown, the enclosure 202 may enclose,protect and/or support an epoxy resin layer 500, a silicone glue layer604, and/or other layer(s) 1000. In the example, the piezo device 600 issecured to an inside surface of the enclosure 202 by a layer of glue602.

FIG. 11 shows a meter 1100 (e.g., a water meter) having two transducerassemblies 200, including respective piezo or ceramic devices 600. Thewater meter 1100 is installed on a water pipe 1102 so that thetransducer assemblies 200 position the piezo or ceramic devices in aposition to receive ultrasonic signals and/or vibrations from the pipe.The transducer assemblies 200 have had their end-caps removed (notshown) so that the open channels 400 of tubes 300 are exposed to theatmosphere of the interior of the enclosure 1104 of the water meter1100. Accordingly, any water and/or humidity passing through the plasticof the enclosures 202 of the transducer assemblies 200 will be exhaustedthrough the channels 400 of the open tubes 300. Once exhausted, thewater will be absorbed by desiccant 1106 within the enclosure 1104 ofthe water meter 1100. The resultant low humidity environment within thetransducer assemblies 200 will protect the glue 602 of holding the piezodevices 600 in place. Accordingly, small amounts of water passingthrough the plastic of the enclosures 202 of the transducer assemblies200 is exhausted through tubes 300 and absorbed by desiccant 1106,thereby resulting in a low humidity environment and longer life of thetransducer assemblies 200.

Examples for Transducer Enclosure with Variable Moisture-Proofing

FIGS. 1 through 11 show examples of a transducer enclosure with variablemoisture proofing. Accordingly, different modes and/or variable moistureproofing may be associated with different respective environments inwhich a transducer, transducer enclosure and/or metering device islocated. In a first example, a transducer assembly includes an enclosureand a transducer located within the enclosure. In the example, a tubedefining a channel may connect an interior of the enclosure and anexterior of the enclosure. An end-cap may be disposed on an end of thetube to prevent ventilation and passage of humidity through the channeldefined in the tube. A frangible portion allows the end-cap is to beremovably coupled to the tube, i.e., the end-cap may be broken off theend of the tube. When the end-cap is installed, it prevents humidityfrom entering the tube and causing damage to the transducer assembly,such as the glue holding the transducer in place. However, in a very wetenvironment, such as when the transducer enclosure is attached to awater pipe, water may slowly migrate through the plastic of theenclosure. By breaking off the end-cap of a tube upon installation, suchwater may be exhausted through the tube, and absorbed by desiccantwithin a utility meter in which the transducer assembly is located.Accordingly, the environment of the transducer device (e.g., a piezodevice) may be keep at a low relative humidity.

In an example, the channel defined in the tube provides sufficientventilation to remove water entering the enclosure when the enclosure isattached to a waterpipe and when the end-cap is removed at the frangibleportion.

In an example, the transducer is a piezo (e.g., piezo electric) deviceglued to an inside surface of the enclosure.

In an example, the enclosure and the end-cap prevent entrance of waterwhen the transducer assembly is in a storage location.

In an example, transducer assembly may include additionally includelayers of waterproof material within the interior of the enclosure todefine a chamber within the enclosure. In the example, the transducermay be located within the chamber. In the example, the layers mayinclude a layer of epoxy and a layer of silicone within the enclosure.In the example, the tube passes through the layer of epoxy and a layerof silicone.

In an example, the enclosure is sufficiently waterproof to prevent entryof water in storage and transfer of the transducer assembly. However,the enclosure may be insufficiently waterproof to prevent entry of waterwhen the enclosure of the transducer assembly is attached to awaterpipe. Accordingly, buy removing the end-cap, any water that entersthe transducer assembly is exhausted through the tube and absorbed bydesiccant.

In an example, the transducer assembly may be located within anenclosure of a water meter. The enclosure of the water meter may alsoinclude a desiccant located outside the enclosure of the transducer andinside the enclosure of the water meter.

In a second example, a transducer assembly may include an enclosure anda transducer located within the enclosure. In the example a tube maydefine a channel connecting an interior of the enclosure and an exteriorof the enclosure. The channel may be defined in the tube to provideenough ventilation to remove water entering the enclosure when thetransducer assembly is attached to a waterpipe.

In the example, the transducer assembly may be part of a water meter.The combined system may also include an enclosure of the water meterwithin which the transducer assembly is disposed, and a desiccantlocated outside the enclosure of the transducer assembly and inside theenclosure of the water meter.

In the example, the transducer assembly may be part of a water meter.Within the combined system, the transducer assembly may be a firsttransducer assembly. In the example, the water meter may include anenclosure of the water meter within which the first transducer assemblyis disposed. The second transducer assembly may also be disposed withinthe enclosure of the water meter.

In the example, the transducer assembly may be part of a water meter.Within the combined system, an enclosure of the water meter may containthe transducer assembly. In an example, the tube provides ventilationbetween the interior of the enclosure of the transducer assembly and aninterior of the enclosure of the water meter.

In an example, the transducer of the transducer assembly is a piezo orpiezo electric device glued to an inside surface of the enclosure.

In an example, a layer of waterproof material(s) within the interior ofthe enclosure define a chamber within the enclosure, wherein thetransducer is located within the chamber, and wherein the tube passesthrough the layer.

In an example, a broken frangible region at an end of the tubeindicating removal of an end-cap of the tube.

In a third example, operation of a metering device is described. In theexample, humidity is prevented from passing through a tube and into anenclosure of a transducer assembly by sealing an end of the tube with anend-cap. In the example, the end-cap is removed from the end of thetube. In the example, the transducer assembly is installed within themetering device. In the example, humidity exhausted from the tube isabsorbed using a desiccant.

In an example, removing the end-cap may be performed by manuallybreaking the end-cap using a frangible region of the tube.

In an example, the transducer assembly may be stored before removing theend-cap. The end-cap will protect the transducer from humidity duringthe storage period.

In an example, the transducer assembly may be operated after removingthe end-cap. During operation, water may enter the transducer enclosuredue to a wet operating environment. However, the water will be exhaustedthrough the tube due to removal of the end-cap, and once exhausted, thewater will be absorbed by desiccant.

In an example, the transducer assembly may be installed for operation byenclosing the transducer assembly within an enclosure of the meteringdevice and enclosing the desiccant within the enclosure of the meteringdevice.

In an example, the transducer assembly may be installed on a water pipeor a gas pipe and may be part of a water meter or a gas meter.

Transducer Enclosure to Protect and Position Transducer Wiring

FIGS. 12 through 22 show examples of a transducer enclosure to protectand position transducer wiring, such as in an automated manufacturingenvironment. In an example, a plug is adapted for connection to anenclosure of an ultrasonic transducer to protect, guide, position and/ororient wiring during storage, transportation, and the manufacturingand/or on-site installation process(s). The plug protects and orientswires to allow for automated manufacturing and to provide an improvedconnection between the transducer and an electronic printed circuitboard. The plug may include a first portion having wire guide(s) and asecond portion configured for attachment to the enclosure of thetransducer. The plug includes at least one wire guide to protect wire(s)that connect the ultrasonic transducer to a printed circuit board. Awire extends through a passage defined in each wire guide in a firstportion of the plug. The first portion slides with respect to the secondportion to expose portions of first and second wires carried within thefirst and second channels, respectively. Once exposed, the wires can besoldered to a PCB in an automated manner.

FIG. 12 shows an example transducer assembly 1200, having an enclosure1204. A wiring guide or plug 1202 is connected to an upper part of theenclosure 1204. In the example, the plug 1202 includes a first portionthat provides two wire guides, and a second portion that connects to theenclosure 1204 of the transducer assembly 1200. In a first position, thefirst portion protects and orients two wires providing a signal from anultrasonic sensor (e.g., piezo device). Sliding the first portion into asecond position within the second portion exposes the wires. The exposedwires may be soldered to a printed circuit board. Accordingly, theenclosure 1204 (for the transducer 1200) and the plastic plug 1202 guideand protect electrical wires, cable and/or wiring guides during storageand transport and may obviate the need for special packaging. Further,when a first portion of the plug is in the second position the wires areexposed, allowing them to be soldered into place.

FIG. 13 shows an example enclosure 1204 for a transducer assembly 1200including a wiring guide or plug 1202 connected to, and/or forming apart of, the enclosure. The plug 1202 may be made of plastic and mayinclude a first portion 1300 that includes one or more wire guides and asecond portion 1302 that attaches to the enclosure 1204. In the exampleshown, the first portion 1300 includes two wire guides 1304, 1306,associated with respective wires 1308, 1310. When the first portion 1300is in the upper position (as shown) the wires 1308, 1310 are protectedby the wire guides 1304, 1306. When the first portion 1300 is moveddownwardly with respect to the second portion 1302, i.e., moved into theenclosure body 1312, the wires 1308, 1310 are exposed.

The second portion 1302 may be glued and/or friction-fit into theenclosure for the transducer. Such fastening means avoids twisting thewires 1308, 1310, although some threaded connections could be used.

In the example shown, several components, regions, and/or materials areincluded within the enclosure 1204 of the transducer assembly 1200. Theexample shows a layer of epoxy resin 500, a layer of silicone glue 604,an ultrasonic sensor 600, and glue 602 holding the sensor in place.

FIGS. 14 through 19 show an example method used to install a meteringdevice on a pipe, including installation of a transducer in an enclosureon the pipe, and including wiring the transducer to a PCB (which may becontained in a metering device, such as a water or gas meter). Thesequence shows example features, structures and techniques of thetwo-portion plug of the housing of the transducer.

FIG. 14 shows the enclosure 1204 of a transducer assembly 1200 mountedon a pipe 1402. The enclosure 1204 of a transducer assembly may beattached with any fastening means, such as clips or clamps 1404. Thewiring guide 1202 (seen edge-on) supports two wires in a pre-determinedlocation. An electronic casing or meter enclosure 1400 is placed on theenclosure 1202 of the transducer assembly 1200. The meter enclosure 1400may be part of a water or gas meter and may protect and enclose one ormore transducer assemblies 1200.

FIG. 15 shows the electronic casing or meter housing 1400 attached tothe housing 1204 of the transducer assembly 1200 by a fastener such as anut 1500.

FIG. 16 shows an electronic printed circuit board (PCB) 1600 that hasbeen place on, and attached to, the electronic casing or meter enclosure1400.

FIG. 17 shows two surfaces 1700, 1702 of the wiring guide or plug 1202.In the assembly process, an automated tool is used to push the uppersurface 1700 to the level of the lower surface 1702. This pushes a firstor upper portion of the plug to side with respect to a second or lowerportion of the plug. While the first portion moves, the wires of thewiring guide do not move, and then become exposed. Accordingly, themovement of the upper surface 1700 lowers the wire guides 1304, 1306,which exposes the wires passing through them (as seen in FIG. 18 ). Theexposed wires are then in position to be soldered to the printed circuitboard.

FIG. 18 shows an exposed wire 1308 (and wire 1310, hidden in the view),which was exposed as the wire guide 1304 (and wire guide 1306, hidden inthe view) of the wiring guide or plug 1202 moved downwardly, as the wireguide as the surface 1700 was pushed to the level of the surface 1702.Accordingly, the wires 1308 (shown, and wire 1310 directly behind wire1308) are at a level slightly higher than the PCB 1600.

FIG. 19 shows the wire 1308 extending from the wire guide 1304 of theplug 1202. An automated tool (not shown) has pushed the wire 1308 intocontact with the PCB. Thus, the wires 1308, 1310 extend just over thetop of the PCB 1600, which locates it appropriately to be soldered tothe PCB.

FIGS. 20A and 20B show a first example of a two-part plug or wiringguide 1202. In the view of FIG. 20A, a first portion 1300 of the plugincludes two wire guides 1304, 1306 and a second portion 1302 attachesto an enclosure 1204 of a transducer assembly 1200 (both seen in FIG. 12). In the view of FIG. 20A, the first portion 1300 is in an extendedposition, which covers and protects the wires of the transducer unit. Anupper surface 1702 and a lower surface 1704 are at different elevations.When in the upper position (as seen in FIG. 17 ) the upper surface 1702may be pushed down to the level of, and flush with, the lower surface1702 (as seen in FIG. 18 ). Such movement of the upper portion 1300 willexpose two wires 1308 (seen in FIGS. 18 and 19 ). Accordingly, FIG. 20Bshows that part of the upper portion 1300 has been pushed down into thelower portion 1302. The wires are not visible in this view for clarity,but are seen in FIGS. 18 and 19 .

FIGS. 21A and 21B show a second example of a two-part plug or wiringguide 2000. The second example differs from the example of FIG. 20 inthat a stop 2002 affirmatively stops motion of the first portion 1300relative to the second portion 1302. In the view of FIG. 21A, a firstportion 1300 of the plug includes two wire guides 1304, 1306 and asecond portion 1302 attaches to an enclosure 1204 of a transducerassembly 1200 (both seen in FIG. 12 ). In the view of FIG. 21A, thefirst portion 1300 is in an extended position, which covers and protectsthe wires of the transducer unit. The stop 2002 and a lower surface 1704are at different elevations. When the upper position the stop 2002 ispushed down to the level of, and flush with, the lower surface 1702.Such movement of the upper portion 1300 will expose wiring of thetransducer device. Accordingly, FIG. 21B shows that part of the upperportion 1300 has been pushed down into the lower portion 1302. The wiresare not visible in this view for clarity, but are seen in FIGS. 18 and19 .

FIGS. 22A-E show example wiring guides (i.e., plugs insertable into anenclosure of a transducer assembly). In the examples, the wiring guidemay include two portions that slide with respect to each other, andwhich are connected to an enclosure of a transducer assembly. In anexample, movement of one portion of the wiring guide results in breakageof a frangible portion of one or both portions of the wiring guide. Inan example of the movement, a first surface 1700 of a first portion ofthe wiring guide is depressed to the level of a second surface 1702 of asecond portion of the wiring guide. In an example of the movement, anautomated tool pushes on surface 1700, thereby breaking the thin plasticarea 2100. The thin plastic area 2100 may be a frangible or breakableseal or perforation. In operation, the surface 1700 and the wire guidesare lowered, until the surface 1700 is flush with surface 1702. Thelowering of the wire guides breaks the seal or perforation 2100. As thewire guides are lowered, wire in the channels defined by each wire guideis exposed. Accordingly, the wire is covered during storage andtransport, but is exposed after movement of the surface 1700 to thelevel of surface 1702.

FIGS. 22D and E shows the first and second portions of a wiring guide1202 in an opposite orientation to that seen in FIG. 22A. A firstportion 1300 and a second portion 1302 are friction-fit, so allow thefirst portion 1300 to slide with respect to the second portion 1302between first and second positions. In the view of FIG. 22D, the firstportion 1302 is in a first position which protects and encloses wiringof the transducer device. In the view of FIG. 22E, the first portion hasslid into a second position, which would reveal the wiring (shown in theviews of FIGS. 18 and 19 ).

As seen in FIG. 22D, ribs 2102 may be defined in the plug, to guide andretain a connection between upper and lower parts of the plug or wiringguide. The wiring guide (e.g., plug 1202 of FIG. 13 and plug 2000 ofFIG. 21 ) may have an upper portion including the surface 1700 (seen inFIG. 21 ) and the two wire guides 1304, 1306 (seen in FIG. 13 ).Additionally, the wiring guide has a lower portion including the surface1702 (seen in FIG. 21 ) and the connecting portion for attachment to theenclosure of the transducer.

Examples of Transducer Enclosure to Protect and Position TransducerWiring

FIGS. 12 through 22 show examples of a transducer enclosure to protectand position transducer wiring, such as in an automated manufacturingenvironment. In a first example of a transducer assembly, a transducerincludes a first wire and a second wire. A housing may at leastpartially enclose the transducer. A plug may be disposed in an openingof the housing. An example plug may include a first portion coupled tothe opening of the housing and a second portion encircling the firstwire and the second wire. In an example, the second portion of the plugis movably coupled to the first portion of the plug, such that thesecond portion is movable from a first position in which the first wireand the second wire are recessed in the second portion, to a secondposition in which the first wire and the second wire protrude from thesecond portion.

In an example, the second portion may include a first wire guide and asecond wire guide. The first wire guide and the second wire guide maydefine a first channel and a second channel, respectively. The firstwire and the second wire may be located at least in part within thefirst channel and the second channel, respectively.

In an example, the first portion may include a first frictional surfaceand the second portion may include a second frictional surface. In theexample, contact between the first frictional surface and secondfrictional surface resists movement of the second portion with respectto the first portion.

In an example, the first portion may include a first frictional surfaceand the second portion may include a second frictional surface incontact with the first frictional surface. In the example, movementovercoming friction between the first frictional surface and secondfrictional surface exposes portions of the first wire and portions ofthe second wire.

In an example, a first channel and a second channel are defined withinthe second portion. In the example, when the second portion is in thefirst position, an end of the first wire and an end of the second wireare enclosed within the first channel and the second channel,respectively.

In an example, a first channel and a second channel are defined withinthe second portion. In the example, when the second portion is in thesecond position, an end of the first wire and an end of the second wireextend out of the first channel and the second channel, respectively.

In an example, the transducer assembly may additionally include acircuit board. In the example, when the second portion is in the secondposition, an end of the first wire and an end of the second wire extendout of a first channel defined in the second portion and a secondchannel defined in the second channel, respectively. In the example, thewires may extend by a distance sufficient for the first wire and thesecond wire to contact the circuit board.

In an example, the transducer assembly may additionally include a stopdisposed on the second portion to limit relative movement of the secondportion with respect to the first portion.

In a second example, a transducer assembly may include a transducerhaving a first wire and a second wire. In the example, a housing may atleast partially enclose the transducer. In the example, a plug may bedisposed in an opening of the housing. In the example, the plug mayinclude a first portion coupled to the opening of the housing and asecond portion. In the example, the second portion may include a firstwire guide and a second wire guide. In the example, the first wire guideand the second wire guide may define a first channel and a secondchannel, respectively. In the example, portions of the first wire andportions of the second wire may be located at least in part within thefirst channel and the second channel, respectively.

In an example, the second portion of the plug may be movably coupled tothe first portion of the plug between a first position and a secondposition. In the example, an end of the first wire and an end of thesecond wire are encased in the first position and exposed when thesecond position.

In an example, the first portion may include a first frictional surfaceand the second portion may include a second frictional surface incontact with the first frictional surface.

In an example, the transducer assembly may additionally include acircuit board. In the example, the second portion of the plug may bemovably coupled to the first portion of the plug, such as to allowmovement between a first position and a second position. In the example,when the second portion is in the second position, an end of the firstwire and an end of the second wire extend out of the first channel andthe second channel, respectively, by a distance sufficient for the firstwire and the second wire to contact the circuit board.

In an example, the transducer assembly may additionally include a stopdisposed on the second portion to limit relative movement of the secondportion with respect to the first portion.

In an example, the first portion may additionally include a firstfrictional surface and the second portion may additionally include asecond frictional surface. In the example, the first frictional surfaceand second frictional surface are in contact.

In a third example, a metering device may be manufactured according toone or more actions and/or techniques. In the example, a housing of atransducer may be attached to a pipe. A printed circuit board (PCB) maybe attached to an assembly adjacent to the housing. A force may beapplied to move a first portion of the housing to expose wires of themetering device. The exposed wires bending the wiring to contact thePCB; and electrically connecting the wiring to the PCB.

In an example, the force applied to move the first portion may includeapplying force to the first portion until a stop contacts a secondportion of the housing.

In an example, the force applied to move the first portion may includeapplying force to the first portion until a surface of the first portionis substantially planar with a surface of a second portion of thehousing.

In an example, the force applied to move the first portion may includeapplying force to break a seal of the housing.

In an example, the force applied to move the first portion may includesliding the first portion against a second portion of the housing.

In an example, the force applied to move the first portion may includesliding wire guides against wires of the metering device to therebyexpose the wires.

Multi-Material Transducer Enclosure

FIGS. 23 through 26 show example designs of transducer assemblies. Thedesigns are made of plastic that includes reinforcing material (e.g.,glass fiber) and/or plastic that does not include reinforcing materialor includes less reinforcing material. In an example, a bi-materialenclosure is configured for use in an acoustic sensor assembly, such asfor use in a water or gas metering applications. A plastic housing withmechanical reinforcements (e.g., 40% glass fiber) provides the advantageof strength and resistance to a high-pressure environment encounteredduring use. Use of a plastic sleeve without fiber reinforcements mayresult in transducer assemblies with more consistent signal transmissioncharacteristics. In some examples, a less-reinforced plastic sleeve mayresult in more homogeneous and/or consistent data from differenttransducer assemblies under the same or similar conditions.

In an example, acoustic signal loss or attenuation may be reduced if amaterial of the less-reinforced sleeve (e.g., sleeve 2506 and endcap2508 of FIG. 25 ) is selected to have an impedance of a piezo deviceand/or water. Additionally or alternatively, the thickness of the sleeveand/or endcap may be selected to be an odd multiple of a quarterwavelength of an acoustic signal to be measured by a piezo and/ortransducer device.

In contrast, use of reinforced material as a sleeve, endcap, and/orother conduit of an acoustic signal may attenuate the acoustic signalbecause of diffraction, deflection, diffusion, dispersion, etc. The useof reinforcing fibers as the signal conduit may result in variations offiber content, variations in fiber alignment, and/or failure of a fibercoating to cohesively contain the fibers and/or to provide an entry pathfor gas, water or other fluid along the fibers. Such entry points may beexposed by, and/or result from, wear during use.

Accordingly, the bi-material transducer enclosure provides a highresistance to pressure, less acoustic signal attenuation, and/or highreproducibility of signal-transmission characteristics betweentransducer assemblies operating under similar conditions.

FIG. 23 shows an example sensor unit or transducer assembly 2300including a transducer device 2302. In the example, a piezo device 2302is shown within the housing 2304. In the example, the housing 2304 ofthe transducer is made of a plastic that is zero percent (oralternatively, 0% to 15%) glass fiber (GF) or other reinforcingmaterial. Advantageously, the housing or enclosure 2304 is consistentwith a high signal level by the piezo device and/or high signaltransmissivity through the housing 2304.

FIG. 24 shows an example sensor unit or transducer assembly 2400including a transducer 2402. In the example, a piezo device 2402 isshown within the housing 2404. In the example, the housing 2400 of thetransducer is made of a plastic that is approximately 40% percent glassfiber (e.g., 15% to 65% glass fiber). Advantageously, a plasticenclosure made with glass fiber provides high strength characteristicsand high resistance to pressure.

FIG. 25 shows an example sensor unit or transducer assembly 2500including a transducer device 2502 (e.g., ultrasonic sensor such as apiezo device). In the example, a piezo device 2502 is shown within thehousing. In the example, the housing has a bi-material design, includingportions that are made of plastic with reinforcing material (e.g., glassfiber) and portions that are made of plastic without reinforcingmaterial. In the example, an outer tube 2504 is made of plastic withfiber and forms a high-strength shell of the sensor unit 2500. An innertube 2506 of the sensor unit 2500 made of plastic without fiber. Theinner tube 2506 also forms, and/or is connected to, an end-portion orcap 2508, which is also made of plastic without fiber.

The sensor unit 2500 provides strength and excellent ultrasonic signaltransmission characteristics. The outer tube 2504 has is stronger thanthe inner tube 2506, and results in a sensor unit 2500 having strengthand resistance to pressure. The inner tube 2506 has better ultrasonicsignal conduction than the outer tube 2504, and the fiber-freeconstruction results in a higher signal level from an ultrasonic sensoror piezo device. Additionally, without variability in fiber content anddistribution, the use of inner tubes made with non-fiber plastic resultsin high signal reproducibility and consistency. That is, the use offiber-free inner sleeves 2506 and end-portions 2508 results inproduction of sensor units that are more similar or homogenous in signaldetection and ultrasonic transducer response, due at least in part totheir fiber-free construction. Additionally, due to the absence of glassfiber plastic in the inner tube 2506, water (e.g., drinking water) isnot contact with glass fiber. Accordingly, the bi-material ultrasonicsensor unit 2500 results in production of transducer assemblies thatprovide excellent and consistent signal transmission from a pipe to apiezo device, high strength and water pressure resistance, and excellentprotection against water contamination.

FIG. 26 shows an example sensor unit or transducer assembly 2600including a transducer device 2602 (e.g., ultrasonic sensor such as apiezo device). In the example, a piezo device 2602 is shown within thehousing. In the example, the housing has a bi-material design, includingportions that are made of plastic with fiber and portions that are madeof plastic without fiber. In the example, a tube 2604 is made of plasticwith fiber, and forms a high-strength shell of the sensor unit 2600. Anend-portion or end cap 2606 of the sensor unit 2600 made of plasticwithout fiber and provides excellent ultrasonic signal transmission froma pipe to an ultrasonic sensor device (e.g., a piezo device).

The transducer assembly 2600 includes both strength and good ultrasonicsignal transmission. The tube 2604 has strength derived in part from areinforced plastic, e.g., glass fiber design, and results in a sensorunit 2600 having considerable strength and resistance to pressure. Theend-portion or end cap 2606 has better ultrasonic signal conduction thanthe tube 2604, and the fiber-free construction results better ultrasonicsignal transfer from a pipe to an ultrasonic transducer device.Additionally, the transducer device will produce a more accurate and/ora higher signal level. Without variability in fiber content anddistribution, the end-portion 2606 made of non-fiber plastic results inhigh signal reproducibility and consistency. Accordingly, thebi-material ultrasonic sensor unit 2600 results in production oftransducer assemblies that provide excellent and consistent signaltransmission from a pipe to a piezo device, and high strength and waterpressure resistance and protection.

Examples of Multi-Material Transducer Enclosure

FIGS. 23 through 26 show examples of an enclosure for a transducer madeof multiple materials, to provide strength and ultrasonic signalconduction.

In a first example, a transducer assembly includes a first tube, asecond tube and an end-portion. In the example, the first tube may bemade of a mechanically reinforced plastic material. The second tube maybe made of a first unreinforced plastic material and may be disposedwithin the first tube. The end-portion may be made of a secondunreinforced plastic material and may be connected to the second tube.

In an example, the mechanically reinforced plastic material comprisesplastic with glass fiber.

In an example, the first unreinforced plastic material and the secondunreinforced plastic material may include plastic free of glass fiber.

In an example, the first unreinforced plastic material and the secondunreinforced plastic material may be the same material.

In an example, the first tube may be made of approximately 40% glassfiber by weight.

In an example, the second unreinforced plastic material of theend-portion attenuates an ultrasonic signal less than the mechanicallyreinforced plastic material of the first tube.

In an example, the transducer assembly may additionally include anultrasonic transducer in contact with the end-portion.

In an example, the transducer assembly may additionally include a piezoelectric transducer in contact with the end-portion.

In an example, the transducer assembly may additionally include anultrasonic transducer. In the example, an outside diameter of theultrasonic transducer is less than an inside diameter of the second tubeand the ultrasonic transducer is coupled to the end-portion.

In an example, the first tube has greater mechanical resistance than thesecond tube and the second unreinforced plastic material of theend-portion attenuates an ultrasonic signal less than the mechanicallyreinforced plastic material of the first tube.

In a second example, a sensor unit for a meter may include a tube, atube-end, and an ultrasonic transducer. The tube may be made of amechanically reinforced plastic material. The tube-end may be made of anunreinforced plastic material. The ultrasonic transducer may be attachedto the tube-end.

In an example, the tube is a first tube, and the sensor unit mayadditionally include a second tube. The second tube may be disposedwithin the first tube and may be made of the same material as thetube-end.

In an example, the mechanically reinforced plastic material may be madeof plastic with glass fiber and the second tube and tube-end may be madeof unreinforced plastic material.

In an example, the first tube has better mechanical resistance than thesecond tube and a material of the second tube and the tube-endattenuates a signal from a pipe less than a material of the first tube.

In an example, the mechanically reinforced plastic material and theunreinforced plastic material are made of a same resin type, but havediffering levels of glass fiber and/or other mechanical reinforcementmaterial.

In an example, the ultrasonic transducer is a piezoelectric transducerin contact with the tube-end.

In an example, the mechanically reinforced plastic material and theunreinforced plastic material are made of a same resin type and themechanically reinforced plastic material comprises glass fiber.

In a third example, a transducer assembly may include a first tube, asecond tube, and an end-portion. In the example, the first tube may bemade of plastic with a reinforcing material and the second tube may bemade of plastic, having less reinforcing material (e.g., glass fiber)than the plastic of the first tube or no reinforcing material (e.g., noglass fiber). In the example, the end-portion may be made of plasticwithout reinforcing material and may be connected to the second tube.

In an example, the transducer assembly may additionally include anultrasonic transducer in contact with the end-portion. In the example,the plastic of the second tube and plastic of the end-portion may bemade of plastic without glass fiber.

In an example, the plastic of the second tube has no glass fiber.

CONCLUSION

Although the subject matter has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described. Rather,the specific features and acts are disclosed as exemplary forms ofimplementing the claims.

What is claimed is:
 1. A transducer assembly, comprising: a transducerenclosure; a transducer located within the transducer enclosure; a tubedefining a channel connecting an interior of the transducer enclosureand an exterior of the transducer enclosure; an end-cap disposed on anend of the tube to prevent ventilation and passage of humidity throughthe channel defined in the tube; a frangible portion by which theend-cap is removably coupled to the tube; and layers of waterproofmaterial within the interior of the transducer enclosure to define achamber within the transducer enclosure, wherein the transducer islocated within the chamber, and wherein the layers comprise: a layer ofepoxy within the transducer enclosure, wherein the tube passes throughthe layer of epoxy; and a layer of silicone within the transducerenclosure and adjacent to the layer of epoxy, wherein the tube passesthrough the layer of silicone.
 2. The transducer assembly of claim 1,wherein: the channel defined in the tube provides sufficient ventilationto remove water entering the transducer enclosure when the transducerenclosure is attached to a waterpipe and when the end-cap is removed atthe frangible portion.
 3. The transducer assembly of claim 1, wherein:the transducer is a piezo device glued to an inside surface of thetransducer enclosure.
 4. The transducer assembly of claim 1, wherein:the transducer enclosure and the end-cap prevent entrance of water whenthe transducer assembly is in a storage location.
 5. The transducerassembly of claim 1, wherein: the transducer enclosure is sufficientlywaterproof to prevent entry of water in storage and transfer of thetransducer assembly; and the transducer enclosure is insufficientlywaterproof to prevent entry of water when the transducer enclosure isattached to a waterpipe.
 6. A water meter comprising the transducerassembly of claim 1, and additionally comprising: an enclosure of thewater meter; and a desiccant located outside the transducer enclosureand inside the enclosure of the water meter.
 7. A water meter,comprising: a transducer assembly, comprising: an enclosure of thetransducer assembly; a transducer located within the enclosure; and atube defining a channel connecting an interior of the enclosure and anexterior of the enclosure; wherein the channel defined in the tubeprovides sufficient ventilation to remove water entering the enclosurewhen the transducer assembly is attached to a waterpipe; an enclosure ofthe water meter within which the transducer assembly is disposed; and adesiccant located outside the enclosure of the transducer assembly andinside the enclosure of the water meter.
 8. The water meter of claim 7,wherein the transducer assembly is a first transducer assembly, and thewater meter additionally comprises: an enclosure of the water meterwithin which the first transducer assembly is disposed; and a secondtransducer assembly disposed within the enclosure of the water meter. 9.The water meter of claim 7, and additionally comprising: an enclosure ofthe water meter within which the transducer assembly is disposed;wherein the tube provides ventilation between the interior of theenclosure of the transducer assembly and an interior of the enclosure ofthe water meter.
 10. The water meter of claim 7, wherein: the transduceris a piezo device glued to an inside surface of the enclosure.
 11. Thewater meter of claim 7, additionally comprising: a layer of waterproofmaterial within the interior of the enclosure to define a chamber withinthe enclosure, wherein the transducer is located within the chamber, andwherein the tube passes through the layer of waterproof material. 12.The water meter of claim 7, additionally comprising: a broken frangibleregion at an end of the tube indicating removal of an end-cap of thetube.
 13. A water meter, comprising: a transducer assembly, comprising:a transducer enclosure; a transducer located within the transducerenclosure; a tube defining a channel connecting an interior of thetransducer enclosure and an exterior of the transducer enclosure; anend-cap disposed on an end of the tube to prevent ventilation andpassage of humidity through the channel defined in the tube; and afrangible portion by which the end-cap is removably coupled to the tube;an enclosure of the water meter; and a desiccant located outside theenclosure of the transducer and inside the enclosure of the water meter.14. The water meter of claim 13, wherein: the channel defined in thetube provides sufficient ventilation to remove water entering theenclosure when the enclosure is attached to a waterpipe and when theend-cap is removed at the frangible portion.
 15. The water meter ofclaim 13, wherein: the transducer is a piezo device glued to an insidesurface of the enclosure.
 16. The water meter of claim 13, wherein: theenclosure and the end-cap prevent entrance of water when the transducerassembly is in a storage location.
 17. The water meter of claim 13, eachtransducer assembly additionally comprising: layers of waterproofmaterial within the interior of the transducer enclosure to define achamber within the transducer enclosure, wherein the transducer islocated within the chamber, and wherein the layers comprise: a layer ofepoxy within the transducer enclosure, wherein the tube passes throughthe layer of epoxy; and a layer of silicone within the transducerenclosure and adjacent to the layer of epoxy, wherein the tube passesthrough the layer of silicone.
 18. The water meter of claim 13, wherein:the enclosure is sufficiently waterproof to prevent entry of water instorage and transfer of the transducer assembly; the enclosure isinsufficiently waterproof to prevent entry of water when the enclosureof the transducer assembly is attached to a waterpipe.
 19. A transducerassembly, comprising: an enclosure; a transducer located within theenclosure; a tube defining a channel connecting an interior of theenclosure and an exterior of the enclosure, wherein the channel definedin the tube provides sufficient ventilation to remove water entering theenclosure when the transducer assembly is attached to a waterpipe; and alayer of waterproof material within the interior of the enclosure todefine a chamber within the enclosure, wherein the transducer is locatedwithin the chamber, and wherein the tube passes through the layer ofwaterproof material.
 20. The transducer assembly of claim 19, wherein:the transducer is a piezo device glued to an inside surface of theenclosure.
 21. The transducer assembly of claim 19, additionallycomprising: a broken frangible region at an end of the tube indicatingremoval of an end-cap of the tube.
 22. A water meter comprising thetransducer assembly of claim 19, wherein the transducer assembly is afirst transducer assembly, and the water meter additionally comprises:an enclosure of the water meter within which the first transducerassembly is disposed; and a second transducer assembly disposed withinthe enclosure of the water meter.
 23. A water meter comprising thetransducer assembly of claim 19, and additionally comprising: anenclosure of the water meter within which the transducer assembly isdisposed; wherein the tube provides ventilation between the interior ofthe enclosure of the transducer assembly and an interior of theenclosure of the water meter.
 24. A water meter comprising thetransducer assembly of claim 19, and additionally comprising: anenclosure of the water meter within which the transducer assembly isdisposed; and a desiccant located outside the enclosure of thetransducer assembly and inside the enclosure of the water meter.